How can I use a custom libc with nixpkgs?

I want to package a custom build of bionic libc (the nixpkgs derivation is prebuilt) but I’m not sure what the best way of overriding the libc package would be outside of nixpkgs. I can only seem to find a way to set it to glibc or musl, not a custom derivation.


1 Like

There’s not package overlay that allows you to just plug in your libc.
If you look into the file pkgs/top-level/stage.nix you will find a definition for pkgsMusl, which builds all packages with musl instead of glibc.
What you need to do is copy that and adapt it to your library.

In any case, I doubt it will be as straightforward as that, I bet you’ll find problems with a lot of packages because practically everyone on Earth assumes libc == glibc.